Apparatus for regulating the output of centrifugal pumps.



Patented May 25 2 SHEETS-SHEET I.

G. SILVESTRI.

APPARATUS FOR REGULATING THE OUTPUT 0F CENTRIFUGAL PUMPS.

APPLICATION FILED )UNE I6, I9I3.

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ll-IE NURRIS PETERs Co., PHOTOALITHO.. WASHING TON. D. C.

G. SILVESTRI. APPARATUS FOR REGULATING THE OUTPUT 0F CENTRIFUGAL PUMPS. APPLlcATloN r|LED1uNE16,:913.

MMLM@ W Patented May25,1915.

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GIULIO SILVESTRI, OF VIENNA, AUSTRIA-HUNGARY.

APPARATUS FOR REGULATING THE OUTPUT OF CENTRIFUGAL PUMPS.

Application led J une 16, 1913.

To all 'whom t may concern Be it known that I, GIULIO SILVESTRI, a citizen of Austria, and resident of Vienna, Lower Austria, Austria-Hungary, have invented certain new and useful Improvements in Apparatus for Regulating the Output of Centrifugal Pumps, of which the following is a specification.

rlhis invention relates to an apparatus for regulating the output of centrifugal pumps in a manner which permits of varying at will at any desired instant the quantity of fluid delivered by the pump between a maximum determined by the capacity of the pump and zero, the load on'the engine driving the pump being reduced in the ratio ofv reduction of the quantity delivered.

ln carrying out the invention there are employed, in conjunction with the pump, a rotary distributing device, an automatic check (non-return valve) and an accumulator, the distributing device being driven at a speed proportionate to that of the pump.

According to the invention, the pressure pipe connected with the pump is short-circuited at intervals with the suction pipe during each revolution of the pump rotor, or piston, so that during periods of time alternating with such intervals the pump delivers part of the iiuid into the delivery part of the pressure pipe i. c. the part of .the pressure pipe lying between the accumulator and the motor, or other device to be operated by the fluid delivered by the pump, and part into an accumulator, the part collected in the accumulator being permitted to flo-w away into the delivery part of the pressure pipe, when the connection of the latter with the pump is interrupted. The accumulator operates simply as an air vessel the function of which is to cause the fiuid delivered in pulsations to discharge as a continuous stream. The intermittent short circuiting of the pump relieves the engine driving the pump, the engine transmitting power tothe pump only in proportion to the quantity of fluid to be delivered.

The apparatus comprises in addition to an accumulator of usual construction interposed in the pressure pipe and a non-return valve interposed in said pipe between the pump and the accumulator, a distributing device which is litted in a short-circuit pipe connecting the pressure pipe with the suction pipe.

, `In the accompanying drawings, the appa- Speccation of Letters Patent.

Patented May 25, 1915.

Serial No. 774,001.

ratus is illustrated diagrammatically in three different operative positions c'. e. for maximum output of the pump in Figure 1, half output in Fig. 2 and for no output in Fig. 3. Fig. A is a longitudinal section of the distributer; Fig. 5 a corresponding cross section; Fig. 6 is a section and Fig. 7 a plan of the movable part of the distributer casing and Fig. S a section and Fig. 9 a plan of the fixed part oi' the distributer casing.

As shown, in the interior of the casing a are formed a passage 7) and a chamber 0,' the passage 5 communicates with the connecting branch d, and the chamber c with the connecting branch e, the said branches Z and c serving according to the direction of rotation, as inlet and outlet for the fluid being pumped. The passage b communicates at several points by means of ports i with the interior of the casing a while the chamber c is directly connected with the reduced end of the cavity formed in the casing.

In the casing is mounted the rotary distributer proper indicated at y", which is of hollow conical form and is continuously rotated at a speed proportional to the number of revolutions of the pump controlled thereby; the said distributer being mounted on a shaft g which is led through the stuffing box it to the exterior of the casing and carries at the outer end the actuating means. ln the instance shown the distributer is driven at the same speed as the pump sha-ft, through the intermediary of chain and sprocket gearing or a belt and pulleys.

In the distributer are arranged ports 7c, which, on rotation of the distributer, register with or are out of register with the ports rlhe end of the distributer adjacent the chamber c is open so that the interior of the distributer is continuously in communication with the chamber c. The distribution of the fluid is therefore always eiiective when the ports and t' are in register.

Between the distributer f and the casing a is fitted a sleeve (Figs. 6 to 9) formed with corresponding ports the size of which determines the duration of the period during which there is a free passage through the ports 7c and z'. As this duration is to be variable, and accordingly, the length of the ports (considered in the direction of the circumference) must be adjustable, the sleeve is formed of two parts fn. and o formed with projections r and s directed toward one another and. engaging each other after the Ybody,

manner of teeth in such manner that in the two extreme positions of the parts in which the pairs of adjacent edges of the projections are close together, the sleeve has as many parts g as there are ports z' in the outer casing of the pump, while in every intermediate position of the two parts double the number of ports and g1 is formed in the sleeve, one half of the number (Q1) being covered Vby solid portions of the wall of the outer casing of the pump and being therefore ineffective.

One part (n) of the sleeve is adjusted and secured within the casing a for example by means of .a ring y' formed with peripheral teeth the spaces between which engage toothlike extensions jl on the part of the sleeve to be fixed, the said ring j being secured to the adjacent cover of the'casing. The location of one edge of each of the projections fr of the part a determines the time of opening of the outlet for the fluid. The other part 0 of the sleeve is adapted to be turned and can be manually adjusted by a lever t mounted on the hollow7 shaft g1 surrounding the shaft g and the stuffing box Zz, of the same and led out of the casing through a second stuffing box h1, The hollow shaft g1 is coupled with the part o ofthe sleeve vby the engagement of a toothed flange g2 with teeth O2 on the rim ofthe sleeve. n

The width o f the projections r and s on the two parts of the sleeve is such that when the projections are close together, openings V`q are formed which are of such length (considered in the direction of rotation) relatively to the .ports 7c in Ethe distributer, that number of the ports 7c on the distributer as illustrated is correspondingly greater than the number of ports in the casing, ,so that one port [c comes into register witha port g in the sleeve ybeforethe preceding port 7a leaves the same kport g in the Qsleeve. In this position (shown in Fig. 3) of ,the part 0 ofthe sleeve the pump delivers no fluidinto .the delivery part 'of the pressure pipe and into the accumulator, as is hereinafter explained. Y

` While the rotary distributer, as it forms La single piece, ,is completely balanced as regards fthe forces (pressures) acting in the Vdirection of rotation, the movable kpart 0 of the sleeve is not so balanced; being subject to a'pressure acting in the direction of the circumference which .tends to bring the part o xof `the sleeve back into the extreme position ,corresponding to the .smallest opening of the inlet pont g. Since these pressures may ghe of considerable lamount the said mov- .able partpf the .sleeve must be balanced with regard to these moments O IZQtation in order i to permit of adjustment of the same by hand. To this end there is caused to act on the lever t (Fig. l) through the intermediary of a rod w1 a piston w which is adapted to be moved within a-cylinder w. The face of the piston remote from the piston rod is under the action of the pressure of the delivery part of the pressure pipe of the pump. The area of the surface of the piston and the distance between the point of connection of the piston rod to the arm t of the lever and the pivot of the same arev so chosen that the product of these two factors is equal to the sum of the pressure surface of the movable part of the sleeve multiplied by their mean distance from the axis of rotation ofthe latter. In this manner two equal moments of rotation are obtained which increase or decrease with increase or reduction of the pres-I sure in the piping and which balance one another since they operate against one another and permit easy adjustment of the sleeve o even with maximum pressures. This apparatus Vis arranged as shown in Figs. l to 3 in the short circuit pipe K connecting the pressure pipe D of the pump P with the suction pipe L; the accumulator S is connected with the part of the pressure pipe lying beyond the (branch) junction of the pipe D with the pipe K, and operates as an ordinary air vessel. The non-return valve 'y arranged between -the'connection of the pipes D and K and the connection of the accumulator with the pipe D closes only when the distributerf of the distributing apparatus permits the passage of the fluid into the pipe K but opens when the pump delivers normally into the pressure pipe D. V"When the ports lc in the rotating distributer 7 are covered by solid wall portions of the casing the entire volume of fluid supplied by the pump must flow through the non-return valve g/ in the pressure Apipe and this volume of fluid is equally distributed vto the delivery part of the pressure pipe and the accumulator S on account of the equal resistance in these parts. Y

If the rotating distributer 7 opens the passage in the short circuit pipe K, the fluid delivered by the pump is brought back through the pipe K into the suction main, since a back pressure operates' from the pressure pipe D on the valve y. The system is thus short-circuited, and since, under Y these conditions, the pump meets no rethe outer casing are covered by solid portions of the wall of the sleeve o (Fig. l) in this case the apparatus V runs idle and may be stopped. Adjustment of the sleeve 0 to increase the size of the ports gcauses a periodical return iiow of a part of the fluid into the suction pipe and only that amount passes into the pressure pipe which is necessary to supplement the returning portion in order to complete the quantity to be delivered.

In Fig. 2 theI apparatus is shown in the mid-position in which the pump discharges into the pressure pipe D z'. e. into the delivery port thereof and into the accumulator only one half of the total amount of fluid delivered. The farther the ports in the sleeve 0 are opened the less is the volume of fluid passing into the pressure pipe z'. e. into the delivery part thereof and into the accumulator and the volume of fluid so passing becomes m'l when the sleeve o is adjusted to the largest opening of the ports g (Fig. If the Huid delivered by the pump be used as the actuating medium for a rotary motor such as indicated by M in dotted lines in Fig. l the speed of rotation of this motor can be varied between a maximum determined by the ratio of the volumes of pump and engine and Zero.

Having described my invention I declare that what I claim and desire to secure by Letters Patent of the United States is l. In an apparatus of the character described, the combination of a pump, pipes connected to said pump constituting a suction pipe and a pressure pipe, a short-circuit pipe connecting the suction pipe with the pressure pipe, a flow interrupter arranged within said short-circuit pipe, said interrupter adapted to be moved at a speed proportionate to that of the pump piston, an accumulator connected to the pressure pipe, and a non-return valve fitted in the pressure pipe between said accumulator and the point of connection of the short-circuit pipe with the pressure pipe.

2. In an apparatus of the character described, the combination of a rotary pump for supplying fluid under pressure, a suction pipe and pressure pipe connected to said pump, a short-circuit pipe connecting the suction pipe with the pressure pipe, a flow interrupter arranged in said pipe and adapted to rotate at a speed proportionate to that of the pump, an accumulator connected to the pressure pipe and operating as an air vessel, and a non-return valve arranged in the pressure pipe between the point of connection of the accumulator with the pressure pipe and the point of connection of the short-circuit pipe with the pressure pipe.

3. The herein described flow interrupter consisting of a casing having two passages, one of which serves as the driving medium inlet and the other as the driving medium outlet, a rotary hollow distributer having a ported wall adapted during its rotation to establish communication at intervals between the driving medium inlet and the outlet, and a sleeve disposed between the casing and the rotary distributor, said sleeve consisting of a stationary part and an adjustable part, said parts having interengaging tooth shaped projections and recesses and serving to determine by the length of some of these recesses the duration of communication between the driving medium inlet passage and the inner space of the distributer.

4. The herein described flow interrupter consisting of a casing having two passages, one of which serves as driving medium inlet and the other as driving medium outlet, a rotary hollow distributer having a ported wall adapted during its rotation to establish communication at intervals between the driving medium inlet and the driving medium outlet, a sleeve disposed between the casing and the rotary distributor, said sleeve consisting of a stationary part and an adjustable part, said parts having interengaging tooth shaped projections and recesses, a hollow shaft on said adjustable part, said hollow shaft extending through the casing, a lever mounted on said hollow shaft, a cylinder and a piston movable within said cylinder, said piston being coupled with the lever and being connected with the pressure pipe of the driving medium.

Signed at Vienna, Lower Austria, Austria-Hungary, this third day of June, A. D.

GIULIO SILVESTRI. Witnesses:

WILHELM BERGER, AUGUST FUGGER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

